JP6804773B2 - Subject visualization device - Google Patents

Description

The present invention relates to a test object visualization device that visualizes a molecular distribution image and a cross section of a test object.

In recent years, genetic diagnosis has made great strides, and it has become an era in which it is possible to individually determine what kind of disease risk is genetically. However, since it is not known until the time of the outbreak of the disease, it is important to detect the outbreak of the disease at an early stage by a less invasive method and to realize a less invasive treatment.

For early detection of disease, it is important to capture functional changes in the pre-stage leading to morphological changes in the subject. In order to capture functional changes, a molecular distribution imaging technique that can visualize the distribution of molecules such as specific proteins in cells or tissues while keeping the tissue structure alive (in vivo) is effective.

The molecular distribution imaging technique using light is roughly classified into a probe method using a fluorescent labeling agent and the like and a non-probe method utilizing the characteristics of substances in the living body. Among the non-probe methods, the molecular distribution imaging technique using CARS (Coherent Anti-Stokes Raman Scatting) has been studied.
Further, in elucidation of the onset mechanism and its progress mechanism of various diseases, detailed spatial position information of the molecule of the test subject is indispensable in order to capture the morphological change of the test subject. Therefore, there is a demand for the molecular distribution imaging technique according to the spatial position information.

OCT (Optical Coherence Tomography) has been developed as a non-invasive morphological imaging technique for living organisms by obtaining the spatial position information. Therefore, a combination of the molecular distribution imaging technique using the CARS and the morphological imaging technique using the OCT has been studied, and the present inventor has also proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-141282

An object of the present invention is to solve the above-mentioned problems in the past and to achieve the following object. That is, an object of the present invention is to provide a test object visualization device capable of simultaneously acquiring a molecular distribution image image and a tomographic image of a test object.

The means for solving the above-mentioned problems are as follows. That is,
<1> A light irradiation unit that irradiates the test subject with the pump light and the Stokes light by varying at least one of the wavelengths of the pump light and the Stokes light generated in the same optical path for each inspection site of the test target. ,
A molecular distribution image image generation unit that detects anti-Stokes light generated from the test subject according to the wavelength difference between the pump light and the Stokes light and generates a molecular distribution image based on the anti-Stokes light.
At least one of the reflected light from the test subject when irradiated with the pump light and the reflected light from the test subject when irradiated with the Stokes light is detected, and the reflected light is based on the detected light. A tomographic image generator that generates a tomographic image of the test subject,
The test object visualization device is characterized by having an image display unit that displays at least one of the generated molecular distribution image image and the tomographic image.

In the test object visualization device according to <1>, the light irradiation unit changes at least one wavelength of the pump light and the Stokes light generated in the same optical path for each inspection site of the test target. The subject is irradiated with the pump light and the Stokes light. The molecular distribution image image generation unit detects the anti-Stokes light generated from the test subject according to the wavelength difference between the pump light and the Stokes light, and generates a molecular distribution image image based on the anti-Stokes light. The tomographic image generation unit has detected and detected at least one of the reflected light from the test subject when the pump light is irradiated and the reflected light from the test subject when the Stokes light is irradiated. A tomographic image of the test subject is generated based on the reflected light. The image display unit displays at least one of the tomographic image generation unit that generates a tomographic image of the test object based on the detected reflected light, the generated molecular distribution image image, and the tomographic image.

Compared with the case where the light irradiation unit generates the pump light and the Stokes light in the same optical path to generate the pump light and the Stokes light in separate optical paths, the optical path from the outlet to the test object. The mirror and space for adjusting the length are not required, and the subject visualization device can be miniaturized.
Further, the test object visualization device irradiates the test object by varying at least one wavelength of the pump light and the Stokes light generated in the same optical path for each inspection location of the test object. A tomographic image of the test subject is generated based on at least one of the reflected light from the test subject when the pump light is irradiated and the reflected light from the test subject when the Stokes light is irradiated. Since the molecular distribution image image is generated based on the anti-Stokes light, the molecular distribution image image and the tomographic image can be acquired at the same time. The three-dimensional molecular distribution image image and the tomographic image can be acquired by XY scanning the pump light and the Stokes light.

<2> The pump light and the Stokes so that the wavelength difference between the pump light and the Stokes light becomes 0 in a range in which the light irradiation unit changes the wavelength of the pump light and the wavelength of the Stokes light. Light is applied to the test subject,
When the tomographic image generation unit irradiates the pump light, the data based on the reflected light from the test subject and the data based on the reflected light from the test subject when the Stokes light is irradiated are obtained. The test object visualization device according to <1>, which generates the tomographic image based on the combined data at a wavelength at which the wavelength difference becomes 0.

In the test object visualization device according to <2>, the light irradiation unit has a wavelength difference between the pump light and the Stokes light of 0 in a range in which the wavelength of the pump light and the wavelength of the Stokes light are variable. The test subject is irradiated with the pump light and the Stokes light so as to be. As a result, the data based on the reflected light from the test subject when the tomographic image generation unit is irradiated with the pump light and the data based on the reflected light from the test subject when the Stokes light is irradiated. By generating the tomographic image based on the combined data at the wavelength at which the wavelength difference becomes 0, the data in the depth direction of the tomographic image can be increased, and the resolution of the tomographic image can be increased. can do.

<3> The above <1> to <2>, wherein the molecular distribution image image generation unit uses the anti-Stokes light as interference light and performs arithmetic processing of Fourier inverse conversion on the spectral interference signal obtained by splitting the interference light. The test object visualization device according to any one.

In the test object visualization device according to <3>, the molecular distribution image image generation unit uses the anti-Stokes light as interference light and performs arithmetic processing of inverse Fourier conversion on the spectral interference signal obtained by splitting the interference light. By doing so, the molecular distribution image can be generated from Winner-Hintin's theorem.

<4> The tomographic image generation unit produces at least one of the reflected light from the test subject when irradiated with the pump light and the reflected light from the test subject when irradiated with the Stokes light. The test object visualization device according to any one of <1> to <3>, wherein the interference light is used and the spectral interference signal obtained by dispersing the interference light is subjected to arithmetic processing for inverse Fourier conversion.

In the test object visualization device according to <4>, when the tomographic image generation unit irradiates the pump light with the reflected light from the test object and the Stokes light with the test object. The tomographic image is generated from Winner Hintin's theorem by using at least one of the reflected light from the light as interference light and performing arithmetic processing of inverse Fourier conversion on the spectral interference signal obtained by dispersing the interference light. Can be done.

<5> The light irradiation unit
An optical parametric crystal that has an optical parametric crystal that converts the wavelength of the light according to the incident angle of the light, and an optical confinement device that traps the light.
The subject visualization according to any one of <1> to <4>, comprising the optical parametric crystal and an optical resonator that shares the optical parametric crystal with the optical confinement device and amplifies the light whose wavelength is converted by the optical parametric crystal. It is a device.

In the light irradiation unit of the test object visualization device according to <5>, the light confiner has an optical parametric crystal that converts the wavelength of the light according to the incident angle of the light, and confine the light. The optical resonator shares the optical parametric crystal with the optical confinement device and amplifies the light whose wavelength is converted by the optical parametric crystal. As a result, the angle of the optical parametric crystal with respect to the optical axis direction of the light is changed, and the light converted into two kinds of wavelengths is amplified by the optical resonator and used as the pump light and the Stokes light. It can be emitted. Further, the wavelength of the pump light and the wavelength of the Stokes light can be changed by changing the angle of the optical parametric crystal.

<6> The <1> to <5> in which the light irradiation unit changes the wavelength of the pump light and the wavelength of the Stokes light so that the vibration band in the molecule of the subject to be tested matches the wavelength difference. The test object visualization device according to any one of.

In the test object visualization device according to <6>, the light irradiation unit sets the wavelength of the pump light and the wavelength of the Stokes light so that the vibration band in the molecule of the test target matches the wavelength difference. By making it variable, the anti-Stokes light can be generated from the molecule possessed by the test subject, so that the molecular distribution image can be generated based on the detected anti-Stokes light. Further, the number of molecules possessed by the test subject may be plural.

<7> The test subject visualization device according to <6>, wherein the molecule possessed by the test subject is at least one of glucose, luteinol, and lutein.

In the test subject visualization device according to <7>, the distribution of molecules involved in the onset of age-related macular degeneration in the fundus retina when the molecule possessed by the test subject is at least one of glucose, rutinol, and lutein. It is possible to diagnose age-related macular degeneration disease at an early stage.

According to the present invention, it is possible to provide a test object visualization device capable of solving conventional problems and simultaneously acquiring a molecular distribution image image and a tomographic image of a test target.

FIG. 1A is an explanatory diagram showing an energy level process until anti-Stokes light is generated in CARS. FIG. 1B is an explanatory diagram showing the relationship between the angular frequencies of the pump light, the Stokes light, and the anti-Stokes light. FIG. 2A is an explanatory diagram showing a resonance process that becomes resonance anti-Stokes light when the excitation level V = 1 of molecular vibration is passed. FIG. 2B is an explanatory diagram showing a non-resonant process that becomes non-resonant anti-Stokes light when the excitation level V = 1 of the molecular vibration is not passed. FIG. 3 is a graph showing the dependence of the signal intensity of anti-Stokes light on the wavelength of Stokes light when the glucose solution is simultaneously irradiated with pump light and Stokes light. FIG. 4 is an explanatory diagram showing a test object visualization device in the example. FIG. 5 is an explanatory diagram showing an example of the relationship between the wavelength tunable range of pump light and Stokes light, the vibration band in the molecule to be tested, and the wavelength of anti-Stokes light.

(Test target visualization device)
The test object visualization device has a light irradiation unit, a molecular distribution image image generation unit, a tomographic image generation unit, and an image display unit, and further has other units as needed.

<Light irradiation part>
The light irradiation unit changes at least one wavelength of the pump light and the Stokes light generated in the same optical path for each inspection site of the test target, and irradiates the test target with the pump light and the Stokes light.

The test subject is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include the fundus.
The inspection location means a location where the molecular distribution image image and the tomographic image of the test subject are desired to be acquired. The inspection site is simultaneously irradiated with the pump light and the Stokes light. The pump light and the Stokes light are simultaneously irradiated, anti-Stokes light is generated according to the wavelength difference between the pump light and the Stokes light, and the molecular distribution image image can be generated based on the detected anti-Stokes light. it can.
The wavelength difference means the difference between the wavelength of the pump light and the wavelength of the Stokes light.
Further, when a plurality of the inspection points are set in the X direction of the test object, a two-dimensional molecular distribution image image and the tomographic image are obtained, and when a plurality of the inspection points are set in the XY direction of the test target, the three-dimensional said A molecular distribution image image and the tomographic image can be obtained.
The same optical path means that the path through which light passes is the same and passes through the same optical system.
Examples of the method of generating the pump light and the Stokes light in the same optical path include a method using optical parametric oscillation.
Examples of the method based on optical parametric oscillation include a method of irradiating a non-linear medium such as an optical parametric crystal with laser light having a predetermined wavelength to generate laser light having different wavelengths.

The pump light is light that is irradiated to the test subject so as to raise the energy level of the molecule of the test subject in order to generate anti-Stokes light from the molecule of the test subject, and in optical parametric oscillation. Is sometimes referred to as "signal light".
The test is such that the Stokes light induces the energy level of the molecule raised by being irradiated with the pump light to a predetermined energy level in order to generate the anti-Stokes light from the molecule possessed by the test subject. It is the light that illuminates the object, and is sometimes called "idler light" in the optical parametric oscillation.
The principle of generating the anti-Stokes light from the molecule of the test target by simultaneously irradiating the inspection site of the test target with the pump light and the Stokes light will be described later.
The wavelength of at least one of the pump light and the Stokes light is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 980 nm or more and 1,150 nm or less. When the wavelength is within the preferable range, it is advantageous in that the molecular distribution image image and the tomographic image in the deep part under the fundus retina can be easily obtained.

The light irradiation unit uses the pump light and the Stokes light so that the wavelength difference between the pump light and the Stokes light becomes 0 in a variable range of the wavelength of the pump light and the wavelength of the Stokes light. It is preferable to irradiate the test subject.

It is preferable that the light irradiation unit changes the wavelength of the pump light and the wavelength of the Stokes light so that the vibration band in the molecule of the test object matches the wavelength difference. Thereby, the anti-Stokes light can be generated from the molecule possessed by the test subject, the anti-Stokes light can be detected, and the molecular distribution image can be generated.
The number of molecules possessed by the test subject may be plural.
The molecule possessed by the test subject is not particularly limited, and a molecule involved in the disease can be appropriately selected depending on the purpose, but glucose is known to be involved in age-related macular degeneration disease. It is preferably at least one of rutinol and lutein.

The light irradiation unit has an optical parametric crystal that converts the wavelength of the light according to the incident angle of the light, and shares the light confinement device and the optical parametric crystal with the light confinement device. It is preferable to include an optical resonator that amplifies the light whose wavelength is converted by the optical parametric crystal.
As a result, the angle of the optical parametric crystal with respect to the optical axis direction of the light is changed, and the light converted into two kinds of wavelengths in the same optical path is amplified by the optical resonator, and the pump light and the pump light and the said. It is emitted as Stokes light.
Further, by changing the angle of the optical parametric crystal, the wavelength of the pump light and the wavelength of the Stokes light can be changed, respectively. In addition, the efficiency of such optical parametric oscillation, stability over time, and stability of the emission positions of the pump light and the Stokes light with respect to wavelength changes are ensured, and nanosecond pulses, picosecond pulses, and femtosecond pulses are ensured. It is possible to correspond to any of the above-mentioned lights.

To improve the efficiency of the optical parametric oscillation, the light is confined by the optical confinement device and passed through the optical parametric crystal a plurality of times to secure the action length of energy conversion from the light to the pump light and the Stokes light. It will be realized by.
The temporal stability of the optical parametric oscillation is realized by shortening the resonator length of the optical parametric oscillation. Further, by matching the optical path length in the optical confinement device with the optical path length in the optical resonator, optical parametric oscillation capable of corresponding to any of the light of nanosecond pulse, picosecond pulse, and femtosecond pulse. To realize.
Further, since the pump light and the Stokes light in the optical resonator reciprocate the optical parametric crystal, the angle of the optical parametric crystal with respect to the optical axis direction of the light is changed, and the light is transferred on the outward path. Even if the position of the optical axis shifts, the position of the optical axis returns on the return path, so that the emission positions of the pump light and the Stokes light can be kept unchanged.
The optical parametric crystal is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include potassium titanium phosphate (KTP).

<Molecular distribution image image generation unit>
The molecular distribution image image generation unit detects the anti-Stokes light generated from the molecule of the test subject according to the wavelength difference between the pump light and the Stokes light, and the molecular distribution image image based on the anti-Stokes light. To generate.
It is preferable that the molecular distribution image image generation unit uses the anti-Stokes light as interference light and performs arithmetic processing of inverse Fourier conversion on the spectral interference signal obtained by splitting the interference light.

The anti-Stokes light is preferably generated from the molecule possessed by the test subject by, for example, CARS (Coherent Anti-Stokes Raman Scattering).
Next, the CARS will be described with reference to FIGS. 1A, 1B, 2A, and 2B.

FIG. 1A is an explanatory diagram showing an energy level process until anti-Stokes light is generated in CARS.
As shown in FIG. 1A, the pulse-oscillated pump light (angular frequency ω _p ) and the pulse-oscillated Stokes light (angular frequency ω _s ) are simultaneously irradiated to the test subject in spite and space. At this time, if the angular frequency difference (Δω = ω _p −ω _s ) between the pump light and the Stokes light is the vibration band in the molecule to be tested, the energy level of the molecule is based on the pump light. As the position V = 0 rises to the upper level, the Stokes light induces the excitation level V = 1. After that, when the test subject is irradiated with the pump light, anti-Stokes light is generated in the process of rising to the higher level and then lowering to the basal level V = 0.
The width of the pulse in the pump light and the width of the pulse in the Stokes light are not particularly limited and may be appropriately selected depending on the intended purpose, but are preferably on the order of picoseconds. As a result, the test subject becomes non-invasive, and the ratio of the resonance signal to the non-resonance signal (hereinafter, may be referred to as “resonance signal / non-resonance signal ratio”) can be easily secured.

FIG. 1B is an explanatory diagram showing the relationship between the angular frequencies of the pump light, the Stokes light, and the anti-Stokes light.
As shown in FIG. 1B, the angular frequency ω _s of the Stokes light and the angular frequency ω _as of the anti-Stokes light are separated by ± Δω about the angular frequency ω _p of the pump light due to the energy level relationship. Exists. That is, the angular frequency of the Stokes light can be expressed by the following equation, ω _s = ω _p − Δω. Further, the angular frequency of the anti-Stokes light can be expressed by the following equation, ω _as = 2ω _p −ω _s = ω _p + Δω.

FIG. 2A is an explanatory diagram showing a resonance process that becomes resonance anti-Stokes light when the excitation level V = 1 of molecular vibration is passed. FIG. 2B is an explanatory diagram showing a non-resonant process that becomes non-resonant anti-Stokes light when the excitation level V = 1 of the molecular vibration is not passed.
As shown in FIGS. 2A and 2B, the anti-Stokes light includes the resonance anti-Stokes light (hereinafter, also referred to as “resonance signal” or simply “anti-Stokes light”) and the non-resonant anti-Stokes light (hereinafter, may be referred to as “anti-resonance signal”) Hereinafter, there are two types (sometimes referred to as "non-resonant signal").
The resonance anti-Stokes light generated through the resonance process is generated from a molecule possessed by the test subject, and is used when generating the molecular distribution image.
The non-resonant anti-Stokes light generated through the non-resonant process is a response involving electronic excitation of water, which is almost independent of the wavelength difference.

<Tomographic image generator>
The tomographic image generation unit has detected and detected at least one of the reflected light from the test subject when the pump light is irradiated and the reflected light from the test subject when the Stokes light is irradiated. A tomographic image of the test subject is generated based on the reflected light.
The tomographic image can be obtained by, for example, OCT (Optical Coherence Tomography), but SS-OCT (Swept Source Optical Coherence Tomography) is preferable.
The tomographic image generation unit uses at least one of the reflected light from the test subject when irradiated with the pump light and the reflected light from the test subject when irradiated with the Stokes light as interference light. , It is preferable to perform arithmetic processing of inverse Fourier conversion on the spectral interference signal obtained by dispersing the interference light.

<Image display>
The image display unit displays at least one of the generated molecular distribution image image and the tomographic image.
The image display unit is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a liquid crystal monitor.

<Other departments>
The other unit is not particularly limited and may be appropriately selected depending on the intended purpose, but it is preferable to have a signal processing unit.
The signal processing unit is not particularly limited and may be appropriately selected depending on the intended purpose. However, the data based on the reflected light from the test subject when the pump light is irradiated and the Stokes light are irradiated. It is preferable to combine the data based on the reflected light from the test object at that time at a wavelength at which the wavelength difference becomes 0.

FIG. 3 is a graph showing the dependence of the anti-Stokes light on the wavelength of the Stokes light when the glucose solution is simultaneously irradiated with the pump light and the Stokes light, and the vertical axis represents the anti-Stokes light. The signal strength (mV) and the horizontal axis are the wavelengths (nm) of the Stokes light. In FIG. 3, the wavelength of the pump light is fixed at 1,064 nm, the wavelength of the Stokes light is changed, and the signal intensity of the anti-Stokes light from the glucose solution is plotted.
As shown in FIG. 3, it can be confirmed that the signal intensity of the anti-Stokes light does not decrease in the range of ± 6 nm centered on 1,209 nm in the wavelength of the Stokes light. From this, it is possible to secure the resolution of the anti-Stokes light in the optical axis direction by detecting the anti-Stokes light as the spectral interference signal in a range of about 10 nm while sweeping the wavelength of the Stokes light. Further, by detecting the reflected light of the Stokes light as the spectral interference signal while sweeping the wavelength of the Stokes light, the spectral interference signal in the depth direction in SS-OCT (Swept Source Optical Coherence Tomography) (hereinafter, "A"). (Sometimes referred to as a line signal) has been acquired, and the tomographic image can be generated.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

FIG. 4 is an explanatory diagram showing a test object visualization device in the example.
As shown in FIG. 4, the test object visualization device 10 includes a light irradiation unit 100, a molecular distribution image image generation unit 200, a tomographic image generation unit 300, a signal processing unit 400, and an image display unit 500. ..
The fundamental wave laser 101 of the light irradiation unit 100 emits a laser beam having a wavelength of 1,064 nm to the dichroic mirror 102. The laser beam is a mode-locked laser beam in which picosecond or femtosecond modes are synchronized.

The dichroic mirror 102 has a non-reflective property for light having a wavelength of 1,064 nm on the S1 surface. Further, the dichroic mirror 102 has a non-reflective characteristic for light having a wavelength of 1,064 nm and a total internal reflection characteristic for light having a wavelength of 532 nm on the S2 surface.

The dichroic mirror 105 has a non-reflective property for light having a wavelength of 532 nm on the S3 surface. Further, the dichroic mirror 105 has a total reflection characteristic for light having a wavelength of 900 nm to 1,200 nm and a non-reflection characteristic for light having a wavelength of 532 nm on the S4 surface.

The total reflection mirror 109 has total reflection characteristics for light having a wavelength of 900 nm to 1,200 nm on the S5 surface.

The output mirror 111 has a 70% PR (Partial Reflection) characteristic for light having a wavelength of 900 nm to 1,200 nm and a total reflection characteristic for light having a wavelength of 532 nm on the S6 surface. Further, the output mirror 111 has a non-reflective characteristic with respect to light having a wavelength of 900 nm to 1,200 nm on the S7 surface.

The space between the dichroic mirror 102 and the total reflection mirror 109 forms a light trap (Cavity) that traps light having a wavelength of 532 nm.
Since the dichroic mirror 102 is provided on the moving stage 103, the optical path length of the optical confinement device can be controlled.

The L-shaped space formed by the total reflection mirror 109, the dichroic mirror 105, and the output mirror 111 forms an optical parametric Oscillation Facility.
In the optical resonator, the signal light and the idler light are amplified each time light having a wavelength of 532 nm passes through the optical parametric crystal 106 in the same optical path, and the signal light and the idler light exceed the threshold value of the output mirror 111. Is emitted from the output mirror 111 as the pump light (indicated by the dotted arrow in FIG. 4) and the Stokes light (indicated by the broken arrow in FIG. 4).
The optical confinement device and the optical resonator share an optical parametric crystal 106. Further, since the total reflection mirror 109 is provided on the moving stage 110, the optical path length of the optical resonator can be controlled. Further, the wavelength of the pump light and the wavelength of the Stokes light generated in the same optical path are obtained by changing the angle of the optical parametric crystal 106 by using the galvano motor 107 to which the galvano drive signal is input from the galvano power supply 108. , Each can be changed.

The moving stages 103 and 110 match the time for the light having a wavelength of 532 nm to reciprocate in the optical confinement and the time for reciprocating in the optical resonator, and a plurality of optical parametric crystals 106 are generated within one pulse period of the light. It is passed through and excited.

Due to the optical parametric oscillation, the pump light and the Stokes light are emitted from the output mirror 111 in a state of overlapping spatially and temporally in orthogonal polarization directions.
The pump light and the Stokes light having two frequencies of orthogonally polarized light pass through a polarizer 112 whose optical axis direction is tilted by 45 ° with respect to the orthogonal axis, so that the pump light and the Stokes light whose polarization directions coincide with each other in the 45 ° direction. It becomes light.

Next, the operation of acquiring the tomographic image will be described.
The pump light and the Stokes light whose polarization directions coincide with each other in the 45 ° direction are separated by a half mirror 113, respectively.

The pump light and the Stokes light, which are divided into two by the half mirror 113, enter the fundus of the eyeball portion 20 as the test object through the galvano mirrors 115 and 116, and at the refractive index boundary portion of the eyeball portion 20. It is reflected and is incident on the half mirror 113 again as the reflected light of the pump light and the reflected light of the Stokes light.

The other pump light and the Stokes light divided into two by the half mirror 113 are reflected by the reflection mirror 301, and the reflection of the pump light from the test object on the half mirror 113 as reference light for obtaining interference light. It overlaps with the reflected light of the light and the Stokes light.
The overlapping reference light and reflected light are separated into the interference light of the pump light and the interference light of the Stokes light by a long-pass dichroic mirror 302 that reflects light having a wavelength of 1,064 nm or more. It is incident on the detectors 303 and 304.

FIG. 5 is an explanatory diagram showing an example of the relationship between the wavelength tunable range of pump light and Stokes light, the vibration band in the molecule to be tested, and the wavelength of anti-Stokes light.
As shown in FIG. 5, the minimum value δ _min and the maximum value δ _max in the range in which the wavelength difference is variable are defined by the following equation, 0 = δ _min <δ, _where δ _n is the vibration band in the molecules of a plurality of test subjects. _{Let n} <δ _max .
For example, as a vibration band in the molecules of the subject, skeletal vibration band [delta] ₁ of glucose 512cm ^-1, C-O vibrational bands [delta] ₂ of Ruchinoru of 1,050Cm ^-1, and 1,159cm ^-1 lutein C- Let the C vibration band δ ₃ be used. In this case, the range for varying the wavelength difference, a ^{0cm -1 <δ <1,400cm -1.} The wavelength of the pump light changes in the range of 990 nm ≤ λ _pump ≤ 1,064 nm, and the wavelength of the Stokes light changes in the range of 1,150 nm ≧ λ _stokes ≧ 1,064 nm.
As a result, the photodetector 303 that detects the Stokes light outputs a spectral interference signal of 1,064 nm ≤ λ _stokes ≤ 1,150 nm, and the photodetector 304 that detects the pump light outputs 1,064 nm ≥ λ. Outputs a spectral interference signal with _pump ≧ 990 nm.

Each of the spectral interference signals is combined by the signal processing unit 400 at a wavelength of 1,064 nm at which the wavelength difference becomes 0, and becomes a spectral interference signal of 990 nm ≦ λ ≦ 1,150 nm. When inverse Fourier transform of the spectral interference signal, the depth resolution, the following equation, Δz = (2ln2) / π · (λ 0 2 a /Derutaramuda)=3.16Myuemu, the A line for generating the tomographic image It becomes a signal. The tomographic image can be obtained by scanning the measurement of the A-line signal in the X direction. In addition, ln is a natural logarithm, λ ₀ is the wavelength of the anti-Stokes light, and Δλ is the step when sweeping the wavelengths of the pump light and the Stokes light.

Next, the operation of acquiring the molecular distribution image will be described with reference to FIG.
The pump light and the Stokes light dispersed by the half mirror 113 are further separated by the half mirror 201.

One of the pump lights and the Stokes light spectroscopically separated by the half mirror 201 passes through water 202 as an anti-Stokes light generation sample and a reflection mirror 203 in order to generate a reference light of the non-resonant anti-Stokes light. It is focused by the lens 213. The non-resonant anti-Stokes light induced at the focusing point is reflected by the reflection mirror 203, condensed by the lens 213, and incident on the half mirror 201 again as parallel light.

The other pump light and the Stokes light divided into two by the half mirror 201 enter the eyeball portion 20 as the subject of the test via the galvanometer mirrors 115 and 116, and are focused by the crystalline lens of the eyeball portion 20 to the fundus retina. Reach. The resonance anti-Stokes light is generated from the molecule of the test subject existing in the fundus retina irradiated with the pump light and the Stokes light. The generated resonance anti-Stokes light is condensed by the crystalline lens and overlaps with the non-resonance anti-Stokes light as reference light for obtaining interference light on the half mirror 201 as parallel light.

The long-pass dichroic mirror 204 that reflects light having a wavelength of 990 nm or more separates the overlapping resonance anti-Stokes light and the non-resonance anti-Stokes light from the pump light and the Stokes light in the same optical axis direction.
The separated resonance anti-Stokes light and the non-resonant anti-Stokes light are separated by a long-pass dichroic mirror 205 that reflects light having a wavelength of 950 nm or more, and the anti-Stokes light (984 nm light) in the vibration mode of the glucose skeleton is glucose-resonated. It enters the photodetector 206 as a signal.
The anti-Stokes light (911 nm light) in the rutinol CO vibration mode and the anti-Stokes light (898 nm light) in the lutein CC vibration mode reflected by the long-pass dichroic mirror 205 are long-pass dichroic mirrors that reflect light with a wavelength of 905 nm or more. It is separated by 208 and is incident on the light detectors 209 and 211 as a rutinol resonance signal and a lutein resonance signal, respectively.

As shown in FIG. 5, in the variable range ^{0cm -1} <δ ^{<1,400cm -1} in wavelength difference [delta], the resonance anti-Stokes light corresponding to 512cm ^-1 glucose skeleton vibration (wavelength 984 nm) is the Ruchinoru the resonance anti-Stokes light corresponding to 1,050Cm ^-1 of C-O vibrations (wavelength 911nm) is, the resonance anti-Stokes light corresponding to 1,525Cm ^-1 of C-C vibration of lutein (wavelength 898nm) is, It occurs in the range of about ± 5 nm from each center wavelength.
These resonance anti-Stokes lights are superposed on the half mirror 201 with the non-resonance anti-Stokes light as the reference light, and are detected by photodetectors 206, 209, and 211.

The outputs from the photodetectors 206, 209, and 211 are spectral interference signals after the DC components are removed by the high-pass filters 207, 210, and 212.
When inverse Fourier transform of the spectral interference signal, the depth resolution, the following equation, Δz = (2ln2) / π · (λ 0 2 / Δλ) = (2ln2) / π · (0.9 2 /0.01)= This is the A-line signal for generating the molecular distribution image image having a size of 35 μm. By scanning the measurement of the A-line signal in the X direction, the molecular distribution image can be obtained.
In the conventional molecular distribution imaging technique using the CARS, scanning in the optical axis direction is required using an optical system having a high numerical aperture, but the spectral interference signal of the anti-Stokes light (CARS light) is used. By performing the inverse Fourier transform, it is possible to eliminate the need for a mechanism for scanning in the optical axis direction.

By the above operation, the molecular distribution image image and the tomographic image of the test subject can be acquired at the same time.
By performing optical scanning not only in the X direction but also in the Y direction, a three-dimensional image of the molecular distribution image in the test object and a three-dimensional image of the morphology can be simultaneously acquired.

10 Subject visualization device 20 Eyeball (test subject)
100 Light irradiation unit 200 Molecular distribution image image generation unit 300 Tomographic image generation unit 400 Signal processing unit 500 Image display unit

Claims (7)

A light irradiation unit that irradiates the test subject with the pump light and the Stokes light by varying at least one of the wavelengths of the pump light and the Stokes light generated on the same optical axis for each inspection site of the test target.
A molecular distribution image image generation unit that detects anti-Stokes light generated from the test subject according to the wavelength difference between the pump light and the Stokes light and generates a molecular distribution image based on the anti-Stokes light.
At least one of the reflected light from the test subject when irradiated with the pump light and the reflected light from the test subject when irradiated with the Stokes light is detected, and the reflected light is based on the detected light. A tomographic image generator that generates a tomographic image of the test subject,
A test object visualization device including an image display unit that displays at least one of the generated molecular distribution image image and the tomographic image. The pump light and the Stokes light are used so that the wavelength difference between the pump light and the Stokes light becomes 0 in a range in which the light irradiation unit changes the wavelength of the pump light and the wavelength of the Stokes light. Irradiate the subject and
When the tomographic image generation unit irradiates the pump light, the data based on the reflected light from the test subject and the data based on the reflected light from the test subject when the Stokes light is irradiated are obtained. The test object visualization device according to claim 1, wherein the tomographic image is generated based on the combined data at a wavelength at which the wavelength difference becomes 0. The test according to any one of claims 1 and 2, wherein the molecular distribution image image generation unit uses the anti-Stokes light as interference light and performs arithmetic processing of Fourier inverse conversion on the spectral interference signal obtained by splitting the interference light. Target visualization device. When the tomographic image generation unit irradiates the pump light, at least one of the reflected light from the test object and the reflected light from the test object when irradiated with the Stokes light is defined as interference light. The test object visualization device according to any one of claims 1 to 3, wherein the calculation process of inverse Fourier conversion is performed on the spectral interference signal obtained by splitting the interference light. The light irradiation unit
An optical parametric crystal that has an optical parametric crystal that converts the wavelength of the light according to the incident angle of the light, and an optical confinement device that traps the light.
The subject visualization apparatus according to any one of claims 1 to 4, further comprising an optical resonator that shares the optical parametric crystal with the optical confinement device and amplifies light whose wavelength is converted by the optical parametric crystal. The invention according to any one of claims 1 to 5, wherein the light irradiation unit changes the wavelength of the pump light and the wavelength of the Stokes light so that the vibration band in the molecule of the test object matches the wavelength difference. Subject visualization device. The subject visualization device according to claim 6, wherein the molecule contained in the subject is at least one of glucose, luteinol, and lutein.

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